Stephen Mangan has joked that movie fans should brace themselves for a "barnet bomb" when they see his latest character on screen.

The comic actor plays former McLaren team manager Alastair Caldwell in Ron Howard's latest movie Rush, about the dramatic events in Formula One racing in 1976.

And the curly-haired star revealed his own moptop wasn't deemed sufficient for the part.

"It's hard to believe they're actually going to have to add hair to mine," he said. "The mind boggles I know, but those dudes from the Seventies really went for it hair-wise."

Stephen quipped: "They've had to send off to Alaska for more hair for me, because they wore it long and low, like dog ears, with sideburns that just won't quit. It's going to be quite a barnet bomb when that goes off."

The star has only just finished the second series of Episodes with Matt LeBlanc, which involved filming in LA in January, and is due back on TV in the first full BBC Four series of Dirk Gently, based on Douglas Adams' quirky detective novels.

He's also part way through voicing Postman Pat for a film version of the classic children's story and, come the summer, he'll be on stage at the Royal Court in London as a pregnant man in futuristic comedy Birthday.

"It's exactly the kind of situation I want to be in," the 43-year-old said of his varied career.